Bypass piston port and methods of manufacturing a bypass piston port for a series progressive divider valve

ABSTRACT

A series progressive divider valve comprises a valve body and pistons. A fluid inlet extend into the valve body. Stations are disposed in the valve body and extend from a first end to a second end; each station comprises piston stations extending through the valve body and a bypass station fluidly isolating the first end form the second end. The piston stations comprise a piston bore and a piston. The bypass stations comprise first and second fluid passages extending from the first and second ends to positions inside the valve body. Outlet bores extend into the valve body, and each comprises first and second sets of outlet bores. Porting forms passageways connecting the stations to each other and with the outlet bores such that when high pressure fluid is applied to the inlet the pistons reciprocates from the first end to the second end in sequence.

BACKGROUND

The present invention relates generally to series progressive dividervalves. More particularly, the present invention relates to fittings forplugging outlet ports such that fluid can be directed to the next outletport in the series progression.

Series progressive divider valves have long-existed in the art andcomprise a mechanism for dividing a single, steady input of pressurizedfluid into multiple, distributed bursts of fluid. Thus, fluid isdelivered to the valve body at a single inlet port and delivered tomultiple discrete outlet ports through cyclic operation of an array ofpistons or spools under pressure from the fluid. The valve output cyclescontinuously through the outlet ports in a scheduled progression basedon movement of the array of pistons. For example, conventional seriesprogressive divider valves include an array of pistons in which thecentral axes of all the pistons are arranged in a single plane. Outletsfor each end of the piston are typically arranged in a plane parallel tothe plane of the pistons. The outlets are connected to the pistonsthrough an elaborate system of portings machined into the valve body.

The pistons reciprocate within bores of the valve body enclosed by endcaps. The pistons themselves include a pair of axially spaced undercutssuch that each piston forms three lobes. As such, when a piston isinserted into a bore and enclosed by end caps, four pressure chambersare formed: one end chamber at each end of the piston and two internalchambers within the piston. Each end chamber is connected to an internalchamber of the next piston in the progression through porting extendingthrough the valve body. Additionally, each internal chamber is connectedto an outlet of the valve through the use of separate porting. Thus, afour piston valve includes eight outlets. High pressure inlet portingconnects each piston bore and, depending on the position of each piston,one of the internal chambers for each piston. All connections andoutlets are made on the same side of the valve body and at the same endsof the pistons, except, however, end chambers of a “first” piston areconnected to internal chambers of a “last” piston such that the pistonscan reverse direction and the series progression can continue adinfinitum.

Operation of a typical series progressive divider valve is explainedwith reference to drawings from the prior art, specifically U.S. Pat.No. 4,312,425 to Snow et al., which shows a simplified piston and outletconfiguration. FIG. 1 shows a perspective view of a typical seriesprogressive divider valve having valve body 10 formed from a pluralityof block bodies 10A-10H. FIG. 2 shows a schematic of valve body 10including pistons 12A, 12B and 12C. FIG. 1 and FIG. 2 are discussedconcurrently. As shown, each of pistons 12A-12C includes three lobes,designated as 14A, 14B, 14C, 16A, 16B, 16C, 18A, 18B and 18C,respectively. Lobes 14A-18C produce undercuts 20A, 20B, 20C, 22A, 22Band 22C, respectively. Pistons 12A, 12B and 12C reciprocate in bores24A, 24B and 24C, respectively, which form end chambers 26A, 26B, 26C,28A, 28B and 28C, respectively. Additionally, undercuts 20A-22C forminternal chambers 30A, 30B, 30C, 32A, 32B and 32C. Each of undercuts20A-22C, and the chamber formed thereby, is fluidly connected to one ofvalve outlets 38A-38F and another undercut via porting machined intovalve body 10. Specifically, internal pumping chamber 30A is fluidlyconnected to end chamber 28C via porting 36A and to outlet 38A viaporting 40A. Internal pumping chamber 30B is fluidly connected to endchamber 26A via porting 36B and to outlet 38B via porting 40B. Internalpumping chamber 30C is fluidly connected to end chamber 26B via porting36C and to outlet 38C via porting 40C. Internal pumping chamber 32A isfluidly connected to end chamber 26C via porting 36D and to outlet 38Dvia porting 40D. Internal pumping chamber 32B is fluidly connected toend chamber 28A via porting 36E and to outlet 38E via porting 40E.Internal pumping chamber 32C is fluidly connected to end chamber 28B viaporting 36F and to outlet 38F via porting 40F.

High pressure porting 42 distributes high pressure fluid from inlet 44to bores 24A-24C. High pressure porting 42 fluidly connects inlet 44 tointernal chambers 30A-32C, depending on the position of lobes 16A-16C.High pressure fluid is always provided directly to one side of each oflobes 16A-16C depending on the position of each of pistons 12A-12C. Asshown, high pressure fluid is provided to internal chambers 32A, 30B and30C. As such, high pressure fluid is also provided to end chambers 26C,26A and 26B, via porting 36D, 36B, 36C, respectively. In the last pistonmovement before the configuration shown in FIG. 2, low pressure fluidhas been dispensed from port 38F via movement of piston 12B downwardthrough porting 36F and 40F. Subsequently, as shown in FIG. 2, highpressure fluid is provided to chambers 26B and 26C. High pressure fluidin chambers 26B and 26C does not produce movement of pistons 12B and 12Cbecause lobes 18B and 18C are already engaged with the end caps of bores24B and 24C. High pressure fluid in chamber 26A will, however, producedownward movement of piston 12A as end chamber 28A discharges lowpressure fluid. Low pressure fluid in end chamber 28A, through porting36E, displaces fluid in internal chamber 32B out of outlet 38E throughporting 40E.

Such displacement of pistons 12A-12C is repeated so long as highpressure fluid is provided to inlet 44, with porting 36D and 36Aconnecting internal chambers and end chambers on opposite ends of thepistons to permit reversing of the axial piston positions. For example,piston 12C moves downward pushing fluid through outlet 38A, piston 12Bthen moves downward pushing fluid through outlet 38F, piston 12A thenmoves downward pushing fluid through outlet 38E, then piston 12C movesupward pushing fluid through outlet 38D, then piston 12B moves upwardpushing fluid through outlet 38C and finally piston 12A moves upwardpushing fluid through outlet 38B.

As mentioned, in order to achieve such cyclic movement, valve body 10 isprovided with an elaborate system of three dimensional porting. Suchporting is produced using a series of machining operations, particularlydrilling, in a plurality of rectangular blocks. For example, valve body10 is produced from blocks 10A-10H as shown in FIG. 1. Blocks 10A and10E comprise “inlet” and “end” blocks with porting necessary to routefluid between pistons at the end of the array. Intermediate blocks10B-10D are identical to each other and include piston bores 24A-24C.Intermediate blocks 10E-10H are identical to each other and includeoutlets 38A-38F. Intermediate blocks 10B-10D are paired withintermediate blocks 10E-10H to form a piston and outlet combination. Inorder to change the number of pistons and outlet ports one pair ofintermediate blocks can be removed. However, such an operation requirestedious and time consuming disassembly and reassembly of the blocks,such as by removal and replacement of screws 46A-46I. Such assemblyintricacies are further detailed are described in the aforementionedU.S. Pat. No. 4,312,425 to Snow et al.

The use of a plurality of separate intermediate blocks reduces oreliminates the need for unnecessary “open ended” drilling operations.These drilling operations are intended to connect other passages, butare not intended to produce a passage that opens to the exterior of thevalve body. However, due to manufacturing limitations the drillingoperations are necessary and the open end must be plugged. For example,two parallel ports may need to be connected by drilling a perpendicularport. The perpendicular port does not, however, need to be opened to theexterior of the valve block. Such ports have typically been closed offusing steel balls welded in place, as is described in U.S. Pat. No.3,467,222 to Gruber. These methods thus require additional manufacturingsteps and additionally introduce potential leak points and stress pointsinto the system.

In other configurations of prior art series progressive valves, outletports 38A-38F can be connected to each other through cross-porting andplugging. In particular, outlet 36C can be ported to connect withoutlets 38A and 38B. Likewise, outlet 38F can be ported to connect withoutlets 38E and 38D. When configured as such, outlet 38B can be pluggedto direct what would be its discharge into outlet 38C so that outlet 38Cwill receive a double shot of fluid. Additionally, outlet 38C can beplugged so outlet 38A can be configured to receive a triple shot offluid. However, in conventional series progressive valves usingintermediate blocks, outlet 38A cannot be plugged because no porting isprovided between outlets 38A and 38B due to the complexity of therequired porting that cannot be introduced into the modular block designof blocks 10A-10H. In other words, the required porting would result ineach intermediate block having a unique configuration. As such, outlet38A becomes a “last stop” outlet that must be permitted to allow fluidfrom valve body 10 because there is not another outlet to which fluidcan be routed. As such if outlets 38A, 38B and 38C were plugged,operation of valve body 10 would seize up. Outlet 38D also becomes a“last stop” outlet for the same reason.

Cross-porting requires blocking of outlet ports with fittings or plugsfrom which it is desired to prevent fluid flow. Such cross-port fittingsare shown in the Quicklub® Progressive Divider Valves brochure for SSV &SSVM Series valves commercially available from Lincoln Industrial, anSKF company. These fittings, however, require the use of severaldifferent plug and ferrule combinations. Other methods of outputcombining involve force fitting brass plugs into the outlets. Theseplugs, however, wear after repeated use and become ineffective.

SUMMARY

A series progressive divider valve comprises a valve body and pistons.The valve body comprises a fluid inlet, stations, outlet bores andporting. The fluid inlet extends into an exterior of the valve body. Thestations are disposed in the valve body and extend from a first end to asecond end; each station comprises a plurality of piston stationsextending axially through the valve body from the first end to thesecond end and at least one bypass station fluidly isolating the firstend form the second end. Each piston station comprises a piston boreconnecting the first end to the second end. A piston is disposed withineach piston bore. Each bypass station comprises a first fluid passageextending from the first end to a first position inside the valve body,and a second fluid passage extending from the second end to a secondposition inside the valve body. The outlet bores extend into the valvebody, and each outlet bore comprises a first set of outlet bores and asecond set of outlet bores. The porting forms a plurality passagewaysconnecting the stations to each other and with the outlet bores suchthat when high pressure fluid is applied to the inlet each of thepistons reciprocates from the first end to the second end in sequence.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art series progressive dividervalve fabricated from several discrete valve body blocks.

FIG. 2 is a diagrammatical view of a cross-section through the prior artseries progressive divider valve of FIG. 1 showing piston boresinterconnected with outlet bores via a network of porting extendingthrough the several valve body blocks.

FIG. 3 is a perspective view of a lubrication system using a seriesprogressive divider valve of the present invention having a unibodyvalve block with four pistons and eight outlets.

FIG. 4 is a perspective view of a second embodiment of a seriesprogressive divider valve of the present invention having a unibodyvalve block with six pistons and twelve outlets.

FIG. 5 is a top view of a third embodiment of a series progressivedivider valve of the present invention having a unibody valve block witha circular arrangement of an eight piston array.

FIG. 6A is a diagrammatic cross-section through a first embodiment ofthe valve block of FIG. 5 taken at section 6-6 showing a bypass pistoninserted in a piston bore.

FIG. 6B is a diagrammatic cross-section through a second embodiment ofthe valve block of FIG. 5 taken at section 6-6 showing a dummy pistonbore.

FIG. 7 is a side view of the third embodiment of the series progressivedivider valve of the present invention having a unibody valve block witha circular arrangement of an eight outlet array.

FIG. 8 is a diagrammatic cross-section through the series progressivedivider valve of FIG. 7 taken at section 8-8 showing bypass passagesconnecting valve outlets.

FIG. 9 is a partially exploded perspective view of the seriesprogressive divider valve of FIG. 3 showing a double-sealed cross-portfitting removed from an outlet.

FIG. 10A is cross-sectional view of a first embodiment of adouble-sealed cross-port fitting in a pass-through configuration.

FIG. 10B is a cross-sectional view of the double-sealed cross-portfitting of FIG. 10A in a bypass configuration.

FIG. 11A is cross-sectional view of a second embodiment of adouble-sealed cross-port fitting in a pass-through configuration.

FIG. 11B is a cross-sectional view of the double-sealed cross-portfitting of FIG. 11A in a bypass configuration.

DETAILED DESCRIPTION

FIG. 3 is a perspective view of lubrication system 100 using unibodyseries progressive divider valve 102 of the present invention havingfour pistons and eight outlets. Lubrication system 100 also includesautomated fluid source 104, manual fluid source 106, hoses 108A and108B, and lubricant destination 110. Valve 102 includes unibody valveblock 112, piston stations 114A-114D, outlets 116A-116G and inlet 118.Manual fluid source 106 is connected to inlet 118 using any appropriatefitting. For example, inlet 118 may comprise a Zerk fitting and manualfluid source 106 may comprise a grease gun. Alternatively, valve 102 maybe connected to automated fluid source 104, such as a large output pump,that provides a greater volume of fluid at a higher pressure.

Valve 102 includes a plurality of pistons disposed within stations114A-114D that provide output to outlets 116A-116G. Outlets 116A-116Gcan be coupled to hoses to provide fluid to a plurality of destinations.As shown, hose 108A connects to fluid destination 110, which comprisesbearing 120. For example, bearing 120 may comprise a wheel bearing in avehicle or a shaft bearing in a machine. Hose 108B can be coupled toanother bearing on another wheel or to some other component of themachine requiring fluid.

Valve 102 receives a single input from inlet 118 and divides the inputinto multiple outputs. Valve 102 also includes a second inlet (notshown) located on the opposite side of valve 102 that can be used as analternative to inlet 118. Although only seven outlets 116A-116G areshown, each piston station 114A-114D provides output to two outlets, onetoward each end of the piston. Pressure provided by manual fluid source106 or automated fluid source 104 activates the pistons within valve 102to cycle through delivering individual bursts of output at each ofoutlet 116A-116G. The pistons continue to cycle output bursts tosuccessive outlets so long as pressurized fluid is provided to inlet118. Valve 102 is therefore typically useful in situations wheremultiple destinations require intermittent small amounts of lubricationrather than steady large amounts of lubrication, such as semi-trailers,construction equipment, wind turbines and complex machinery.

Valve 102 is comprised of a single block of material, typically steel orsome other metal, forming valve block 112. Valve 102 comprises aparallelepiped body having six surfaces in the described embodiments,but may comprise other shapes. In the present invention, piston stations114A-114D are configured perpendicular to outlets 116A-116G. Forexample, valve 102 includes piston faces 122A and 122B through whichdrilled bores extend to receive the pistons. The drilled bores areplugged with end caps, such as caps 123A-123F, to retain the pistons andform piston stations 114A-114D. Outlets 116A-116G are provided by boresextending into outlet faces 124A and 124B. Outlets 116A-116G includefittings that can be configured to couple to hoses or configured toroute output to another outlet. For example outlets 116A-116D includefittings 125A-125D.

Valve block 112 can be configured with different numbers of pistonstations and different numbers of active piston stations, which differsthe number of outlets and active outlets. As shown in FIG. 3, valveblock 112 is ported for four pistons and eight outlets. As shown in FIG.4, valve block 112 is ported for six pistons and twelve outlets. Asshown in FIGS. 5 and 7, valve block 112 is ported for eight pistons andsixteen outlets. FIGS. 6A and 6B show how piston stations can bebypassed to reduce the number of active piston stations and outlets fora particular valve block configuration. FIGS. 5 and 7 further show howvalve stations 114 and outlets 116 can be arranged in circular patternsto facilitate manufacturing and improve performance. FIG. 8 shows howcircularly arranged outlets 116 can be plumbed together to enablecross-port fittings that reduce the number of active outlets. FIGS.9-11B show various cross-port fittings that can be used in outlets 116.

In each configuration depicted in FIGS. 3-11B, each piston station 114and outlet 116 is analogous, unless specified otherwise. The onlychanges from one embodiment to another being the number of pistons andthe diameter of circles around which the piston stations and outlets arearranged. As used throughout the specification, analogous components,such as piston stations, pistons, outlets, end caps, etc., areidentified using a common reference numeral. Each reference numeral isassociated with a reference letter specific to each Figure such that theletter does not necessarily correspond to a letter from another Figure,unless specified otherwise. For example, FIG. 3 refers to pistonstations 114A-114D, while FIG. 4 refers to piston stations 114A-114F.Piston station 114A of FIG. 3 is not piston station 114A of FIG. 4, buteach is functionally equivalent.

With respect to operation of the present invention, the various seriesprogressive divider valves of FIG. 3-FIG. 11B perform in the samegeneral manner as that which is described with reference to FIG. 2 froma schematic fluid flow standpoint. Series progressive divider valves ofthe present invention, however, include novel porting and borearrangements not shown in FIG. 2 that connect the various pistonchambers and outlets, which are produced from novel manufacturingprocesses and methods. FIG. 2 is presented for ease of explanation ofthe operation of series progressive divider valves in general. Thus, thepresent invention performs everything described in FIG. 2, but FIG. 2does not describe everything in FIGS. 3-11B.

FIG. 4 is a perspective view of a second embodiment of unibody seriesprogressive divider valve 102 of the present invention having six pistonstations and twelve outlets, of which stations 114A-116F and outlets116A-116J are shown. Each of piston stations 114A-114F is shown closedoff by a cap, analogous to caps 123A-123F of FIG. 3.

Similarly, each of outlets 116A-116J is shown connected to a fitting,analogous to fittings 125A-125D of FIG. 3. As mentioned above, valveblock 112 is formed of a single piece of material into which stations114 and outlets 116 are machined. Furthermore, all machining operationrequired to fluidly link piston stations 114 and outlets 116 can beperformed through the bores machined for piston stations 114 and outlets116. Such machining operations are enabled by placement of pistonstations 114A-114F between piston faces 122A and 122B and placement ofoutlets 116A-116F between outlet faces 124A and 124B. Furthermore, themachining operations are enabled by arrangement of piston stations 114in a circle-like pattern, as discussed with reference to FIG. 5.Additionally, arrangement of outlets 116 in a circle-like pattern allowseach outlet on its respective outlet face 124A or 124B to be connectedto both adjacent outlets on the outlet face, as discussed with referenceto FIG. 7.

FIG. 5 is a top view of a third embodiment of unibody series progressivedivider valve 102 of the present invention showing valve block 112having eight piston stations 114A-114H arranged in a circular array.Each of piston stations 114A-114H comprises one of piston bores126A-126H. Piston stations 114A-114H are arranged along circle 128 andaround center point 130. FIG. 6A is a diagrammatic cross-section througha first embodiment of valve block 112 of FIG. 5 taken at section 6-6showing piston bores 126A-126C and bypass piston 132 inserted intopiston bore 126B and pistons 134A and 134C inserted into piston bores126A and 126C, respectively. Piston bores 126A-126C are provided withend caps 123A-123F. FIGS. 5 and 6A are discussed concurrently.

In FIG. 5 piston stations 114A-114H are shown without end caps 123A-123Fsuch that piston bores 126A-126H are visible. Piston bores 126A-126Hextend into piston face 122A of valve block 112 through to piston face122B, as shown in FIG. 6A. Piston bores 126A-126H are connected by anetwork of porting to permit fluid to pass from one bore to the next, ascan partially be seen in FIG. 6A. For example, piston bores 126A-126Cinclude porting 136 and 138A-138D. Piston bores 126A-126C also includeother features to facilitate connection of end caps 126A-126F andporting 138A-138D. For example, piston bores 126A-126H include counterbores 140A-140H, undercuts 142A-142F and undercuts 143A-143D.

Pistons 134A and 134C are inserted into bores 126A and 126C and sealedtherein by end caps 123A and 123D and end caps 123C and 123F,respectively. Similarly, bypass piston 132 is inserted into piston bore126B and enclosed therein by end caps 123B and 123E. End caps 123A-123Fare, for example, threaded into mating threads lining counterbores140A-140C and 140I-140K and sealed with O-rings. Once inside bores 126Aand 126C, pistons 134A and 134C form end chambers 144A-144D between theends of the pistons and the end caps. Additionally, pistons 134A and134C include undercuts 146A-146D that form internal chambers 148A-48D.

Pistons 134A and 134C and bypass piston 132 are subject to high pressureinlet fluid from porting 136, which connects internal chambers 148A-148Dto each other and to internal chambers of other pistons not shown.Pistons 134A and 134C are subject to high pressure in end chambers 144A,144C, 144D and 144F that causes reciprocating motion consistent with thedescription above. Bypass piston 132 is, however, substantially equal inlength to the length of piston chamber 126B such that reciprocatingmotion is inhibited. Specifically end surfaces of bypass piston 132engage end caps 123B and 123E. Bypass piston 132 does not includeundercuts that produce internal chambers. Bypass piston 132 includescentral portion 150 that is substantially the same diameter as pistonbore 126B to form a seal having very small gap. Central portion 150 alsoincludes grooves for receiving 0-rings 152A and 152B that close the gap.Central portion 150 divides piston bore 126B into first and second fluidpassages. Bypass piston 132 also includes necked-down end portions, orflow portions, 154A and 154B that extend inside piston bore 126B fromundercuts 142B and 142E to end chambers 144B and 144E, respectively. Assuch, bypass piston 132 is a dummy piston that permits fluid frompassages 138A-138D to simply pass through piston bore 126B in routebetween piston bores 126A and 126C without distributing a burst of fluidto an outlet. Outlets 116 machined into valve block 112 for piston bore126B are plugged with a sealed fitting. Bypass piston 132 thus providesone means for reducing the number of active piston stations and activeoutlets within block 112 without the need of changing the geometry ofvalve block 112 and the porting machined therein. Thus, for example,valve block 112 of FIG. 5 can be reduced from eight active pistons toseven active pistons. Configured as such, the valve block is convertedback to eight active pistons by removing the dummy piston and any sealedfittings.

The reciprocating of pistons 134A and 134C requires close tolerancesbetween the outer diameter of each piston and its associated pistonbore. Machining of bores 126A-126H is thus an important step inmanufacturing of valve 102 due to the close tolerances that must beachieved between the pistons and the bores. For example, the pistonsform a metal-to-metal seal inside bores 126A-126H to prevent fluid fromleaking between internal chambers and end chambers formed by the piston.As such, each of bores 126A-126H is first roughly located using a drill.Next other features of each of piston stations 114A-114H are machinedinto bores 126A-126H. For example, counterbores 140A-140H can be formedusing a counterbore cutter and undercuts 142A-142F can be formed using aWoodruff cutter. The last step in producing piston bores 126A-126Ccomprises honing of the bores, which produces a smooth bore with verytight tolerances.

As shown in FIG. 5, piston stations 114A-114H are arranged along circle128, which is centered around center point 130 to facilitate manufactureof valve block 112. Circle 128 comprises a geometric path that extendsin a plane parallel to piston face 122A and intersects each of bores126A-126H. In one embodiment, circle 128 includes a circumference thatintersects the center of each of bores 126A-126H. Center point 130 isequidistant from each of the centers of bores 126A-126H and bores126A-126H are distributed equally around the circumference of circle128. As described, piston bores 126A-126H are arranged in a circulararray. This results in piston bores 126A-126H also having a polygonaloutline. As shown in FIG. 5, piston bores 126A-126H are arranged in anoctagonal outline. As shown in FIG. 4, piston bores 126A-126F arearranged in a hexagonal outline. As shown in FIG. 3, piston bores126A-126D are arranged in a square outline.

Center point 130 comprises an indentation or notch into which amachining support can be inserted to reference machining points forbores 126A-126H. Specifically, valve block 112 is positioned within acradle that secures the block and rotates with respect to a cuttingtool. Center point 130 provides an index point for the cutting tool witha fixed distance from each piston station. As such, the first rough-cutpiston bore can be honed with the cutting tool by descending andretreating the cutting tool into the piston bore. The cradle thenrotates valve block 112 a fixed amount equal to the desired spacingbetween piston bores along circle 128. The location of the next pistonbore to the cutting tool once the cradle rotates is the same as for theprevious piston bore. Thus, the cutting tool need only descend intoblock 112 and retreat without further indexing. The process is repeatedfor each rough-cut piston bore. By locating the piston bores around acircle, the honing process can be precisely executed with minimalrepositioning of block 112 and the machining equipment. Furthermore,center point 130 is located at the center of gravity of block 112 suchthat block 112 is balanced, reducing the time needed for the cradle toposition block 112.

After piston bores 126A-126C are completed, or before the honing step iscompleted, porting 136 and porting 138 is machined into block 112.Machining of porting 136, for example, requires precise placement suchthat piston bores 126A-126C are opened at the desired time and placewith respect to movement of pistons 134A and 134C. For example, it isdesirable for internal chamber 148A to be opened by undercut 146A ofpiston 134A at approximately the same time internal chamber 148B isopened by undercut 146B such that fluid volume can be equally displacedthroughout valve 102. Ports 138A-138D are small holes relative to thedistance the drill bit must travel to produce the bore. That is, thediameter of the bores is small compared to the length of the bores.Typically, under such circumstances the drill bit has a tendency to“walk” as it progresses through the material. This makes predicting theexact location where the drill bit will pierce the piston bore somewhatunpredictable, at least to the accuracy required for precise opening ofthe piston bores.

With reference to FIG. 6B, the present invention utilizes a two-stagedrilling process in conjunction with undercuts 142C and 142F toalleviate problems associated with drill bit walk. Porting 138B and 138Dcomprise diagonal passageways connecting end chambers 144A and 144D toundercuts 142C and 142F, respectively. Porting 138B and 138D are formedby performing machining operations inside piston bore 126C. First,porting 138B and 138D are partially drilled using a drill bit having afirst diameter to form a first length of the porting extending over backbores 156B and 156D, respectively. The first diameter is large relativeto the length of porting 138A-138D to minimize walking. Back bores 156Band 156D permit a smaller diameter drill bit to be inserted into valveblock 112 a closer distance to piston bore 126C such the a smallerdiameter drill bit is used to pierce undercuts 142A-142F. The smallerdiameter drill bit need only traverse a second length of the portingthat is shorter than the overall length to again minimize walking.

Undercuts 142A-142F are precisely positioned using the Woodruff cutter,which can be positioned directly adjacent to piston bore 126C in thelocation desired. Specifically, undercuts 142A-142F are positioned atthe exact point where it is desired for internal chambers 148B and 148Cto open. Undercuts 142A-142F comprise a void adjacent to piston bores126A that increases the local cross-sectional area of the bore.Undercuts 142A-142F extend completely around the circumference of pistonbores 126A and 126C. Undercuts 142A-142F thereby produce a largersurface area for drill bits to intersect. Specifically, undercuts142A-142F result in a pair of horizontal (with respect to FIG. 6B)surfaces that intersect piston bore 126C at right-angles and at precisepositions. Undercuts 142A-142F result in a single vertical (with respectto FIG. 6B) surface that produces a large target for the drill bit tointersect. The height of the vertical surface is larger than thediameter of the smaller diameter drill bit used to connect back bores156B and 145D with undercuts 142C and 142F. The resulting geometry is acylindrical undercut. The precise location at which the drill bitintersects the vertical surface is not important as the undercutscompletely encircle the horizontal surfaces. So long as the drill bitpierces the vertical surface, porting 138B will be fluidly connectedwith internal passage 148B, with the horizontal surfaces ensuring thatthe connection occurs at the desired location. Such drilling andmachining processes reduces the number of valve blocks 112 that areproduced out-of-spec and increases the accuracy of the volumetric outputof valve 102.

Undercuts 143 improve the operation of valve 102 in other ways. Forexample, undercuts 143A and 143B reduce point loading on piston 134A.For example, as shown in FIG. 6B, porting 165A intersects piston bore126A off to the side of piston 134A. Likewise, porting 1651 intersectspiston bore 126A off to the side of piston 134A. Ordinarily, withoutundercuts 143A and 143B, fluid traveling through porting 165A and 1651and into internal chambers 148A and 148D (when undercuts 146A and 146Bof piston 134A are so positioned) would impact piston 134A at only aportion of the circumference of undercut 143A or 143B. Thisdisproportion would result in a slight disturbance to the reciprocationof piston 134A within piston bore 126A, increasing wear at pistonstation 114A. Undercuts 143A and 143B, however, distribute the force ofincoming fluid around the entire circumference of piston 134A. As such,linear reciprocating motion of piston 134A is not disturbed in theradial direction with respect to piston bore 126A.

With reference to FIG. 6B, a second means for reducing the number ofactive piston stations and active outlets within block 112 without theneed of changing the geometry of valve block 112 and the portingmachined therein. The embodiment of FIG. 6B is machined in the same wayas the embodiment of FIG. 6A with the exception that piston bore 126B isnot extended through from piston face 122A to piston face 122B.Additionally, undercuts 142B and 142E (FIG. 6A) are omitted. Piston bore126B is replaced by stub bores 158A and 158B. Stub bore 158A extendsinto piston face 122A far enough to intersect porting 138A at a firstposition. Stub bore 158B extends into piston face 122B far enough tointersect porting 138C at a second position. This intersection occurswhere undercuts 142B and 142E would be positioned. Except in thisscenario, precise intersection of stub bores 158A and 158B with porting138A and 138C is not needed as fluid need only pass from the porting138A to porting 138B and from porting 138C to 138D to convey the fluidto internal chambers 148B and 148C where undercuts 142C and 142F arelocated. Thus, for example, valve block 112 of FIG. 5 can be reducedfrom eight active pistons to seven active pistons.

Stub bores 158A and 158B can be machined into valve block 112 using asub-set of the machining instructions used to machine piston bores 126Aand 126C. For example, instead of drilling piston bore 126B, stub bore158A and stub bore 158B are machined. However, additional machiningsteps are the same, such as those for counterbores 140B and 140J andporting 138A and 138C. Machining for undercuts 142B and 142E is simplyomitted. This results in stub bores 158A and 158B having an envelope ofremoved material that fits within an envelope required for machining ofa piston bore. Therefore, if desired stub bores 158A and 158B could beconverted into a piston bore by simply re-machining valve block 112 withthe instructions for machining a piston bore at the location of stubbores 158A and 158B. Specifically, the portion of material of block 112forming the divider between stub bores 158A and 158B can be machinedaway and undercuts 142B and 142E added.

FIG. 7 is a side view of the third embodiment of series progressivedivider valve 102 of the present invention showing valve block 112having eight outlets 116A-116H arranged in a circular array. Each ofoutlets 116A-116H comprises one of outlet bores 160A-160H. Outlets116A-116H are arranged along circle 162 and around inlet 118. Outletbores 160A-160H connect bypass passages 164A-164H with porting165A-165H, which extend into valve block 112 to connect to an undercut143 that engages one of undercuts 146A-146F (FIG. 6A) of pistons 134.FIG. 8 is a diagrammatic cross-section through series progressivedivider valve 102 of FIG. 7 taken at section 8-8 showing bypass passages164A-164D connecting valve outlets 160A-160D. FIG. 8 shows cross-portfittings 166A-166D coupled to outlets 116A-116D. In FIG. 7, cross-portfittings are omitted such that outlet bores 160A-160H are visible. FIGS.7 and 8 are discussed concurrently.

As shown in FIG. 7, outlet bores 160A-160H are arranged along circle162, which is centered around inlet 118. Circle 162 comprises ageometric path that extends in a plane parallel to outlet face 124A andintersects each of outlet bores 160A-160H. In one embodiment, circle 162includes a circumference that intersects the center of each of bores160A-160H. Inlet 118 is equidistant from each of bores 160A-160H andbores 160A-160H are disctributed equally around the circumference ofcircle 162. As described, bores 160A-160H are arranged in a circulararray. This results in bores 160A-160H also having a polygonal outline.As shown in FIG. 7, bores 160A-160H are arranged in an octagonaloutline. Outlet bores 160A-160H need not, however, be arranged in a truecircular array. For example, bores 160A-160H could be arranged around anoval array or a polygonal array. Two outlet bores, however, must bealigned with each piston bore. Specifically, outlet bores 160A-160H arearranged in a proximal configuration such that each outlet can beconnected to an open loop fluid path that connects all of the outlets oneach of outlet faces 124A and 124B.

With outlet bores 160A-160H arranged in a circular array, they are closeenough to each other to allow adjacent porting of porting 165A-165H toconnect to each other. Such an arrangement of circular porting ispermitted due to the fact that outlets 116A-116H are provided on a pairof surfaces, outlet faces 124A and 124B, that are perpendicular to apair of surfaces, valve faces 122A and 122B, in which piston stations114A-114H are provided. Such a circular arrangement permits valve block112 to be fashioned in a more compact manner. Such an arrangement alsoavoids the need for using an “inlet” block and an “end” block, asdescribed above with reference to the prior art, and allows the outletsto be connected as described here. As such, valve 102 does not includeany “last stop” outlets that cannot be plugged with a cross-portfitting.

Outlet bores 160A-160H extend into outlet face 124A only so far as toconnect to porting 165A-165H. Each of bypass passages 164A-164H connectsone of outlet bores 160A-160H to an adjacent one of porting 165A-165H.Bypass passages 164A-164H do not necessarily extend through the centersof bores 160A-160H such that they do not form a true circle. Bypasspassages 164A-164H, however, to give rise to the polygonal outlinementioned above. Bypass passages 164A-164H are angled such that a drillbit can be inserted into outlet bores 160A-160H to intersect porting165A-165H. Bypass passages 164A-164H, with porting 165A-165H, form anopen loop flow path into which fluid from any of the outlets can berouted. As shown in FIG. 8, outlet bores 160A-160D are coupled tocross-port fittings that can be configured to only permit fluid intocouplings 168A-168D, as fittings 125A, 125B and 125D are configured, orto permit fluid into coupling 168A-168D to flow into bypass passages164A-164D with the aid of a plug, as fitting 125C is configured withplug 169 using threaded engagements 170.

FIG. 9 is a partially exploded perspective view of series progressivedivider valve 102 of FIG. 3 showing double-sealed cross-port fitting125B removed from outlet 116A. Cross-port fitting 125B includes adapter171, first seal 172 and second seal 174. As discussed with reference toFIG. 7, outlets 116A-116D include bypass passages 164A-164D that permitfluid to flow from one outlet to the next. However, it is not desirableto always have outlets 116A-116D connected to each other. Seals 172 and174 of cross-port fitting 125B can be configured to permit fluid to flowfrom outlet bore 160B through to coupling 168A (FIGS. 10A and 11A), orto flow from outlet bore 160B through to bypass passage 164B with theuse of plug 170 (FIGS. 10B and 11B).

FIG. 10A is cross-sectional view of a first embodiment of double-sealedcross-port fitting 125B in a pass-through configuration. Cross-portfitting 125B includes adapter 171, first seal 172 and second seal 174.Adapter 171 includes coupling segment 176, which includes first diameterportion 176A and second diameter portion 176B. Adapter 171 formscoupling 168B (FIGS. 8 & 9) to which an outlet hose can be coupled orinto which plug 170 (FIG. 9) can be fitted. First diameter portion 176Acomprises a ring segment extending radially outward from axiallyextending portion 176. First diameter portion 176A includes threads 178that engage mating threads in outlet bore 160B. First diameter portion176A forms groove 179 in coupling segment 176. Second diameter portion176B comprises an axial extension from first diameter portion 176Ahaving a smaller diameter. Second diameter portion 176B includes groove180 into which second seal 174 is positioned. First seal 172 ispositioned in groove 179 adjacent chamfer 184 in outlet bore 160B.Internal passage 184 extends through coupling segment 176 and intoadapter 171 to intersect coupling 168A. Adapter segment 176 thus forms asidewall surrounding passage 184.

Coupling segment 176 is inserted into outlet bore 160B such that adapter171 engages the exterior of valve block 112. Threaded engagements 178 offirst diameter portion 176A engage mating threads in outlet bore 160B.Additionally, internal passage 184 meets up with porting 165B and bypasspassage meets up with first diameter portion 176A. Inserted as such, thebottom of groove 179 and the bottom of groove 180 face radially awayfrom passage 184 and toward outlet bore 160B.

In the embodiment shown, first seal 172 comprises a rubber 0-ring fittedaround the bottom surface of groove 179. When fitting 125B is assembledwith outlet bore 160B, seal 172 is compressed between groove 179 andchamfer 182 to prevent leakage of fluid from valve body 112.Specifically, fluid present in bypass passage 164B, such as from theoutlet at the end of bypass passage 164B not shown, is prevented frommigrating out of valve body 112. Likewise, second seal 174 comprises arubber O-ring fitted around the bottom surface of groove 180. In otherembodiments, seals 172 and 174 may comprise other types of O-rings orother types of seals, as discussed with reference to FIGS. 11A and 11B.When fitting 125B is assembled with outlet bore 160B, seal 174 iscompressed between groove 180 and outlet bore 160B to prevent leakage offluid from valve body 112. Specifically, fluid from porting 165B isprevented from passing between coupling segment 176 and valve block 112to reach bypass passage 164B. Seal 174 blocks the fluid from engagingthreaded engagements 178. As such, all fluid from porting 165 is routeddirectly into passage 184 and out fitting 125A. Thus, a hose connectedto coupling 168A, which includes threaded engagements 170 (FIG. 8), willreceive fluid distributed by valve 102. Seal 174 can be removed andcoupling 168A capped with plug 170 to redirect fluid from porting 165Binto bypass passage 164B.

FIG. 10B is a cross-sectional view of double-sealed cross-port fitting125B of FIG. 10A in a bypass configuration. In FIG. 10B, seal 174 isremoved from groove 180, but seal 172 remains in groove 179. Plug 170 isthreaded into coupling 168A to block fluid flow through adapter 171. Assuch, porting 165B is fluidly coupled with bypass passage 164B. Seconddiameter portion 176B has a diameter slightly smaller than the portionof outlet 160B immediately surrounding portion 176B such that fluid maypass between. Second diameter portion 176B also has a diameter smallerthan that of first diameter portion 176A such that fluid flow is impededfrom traveling towards first seal 172. First diameter portion 176A alsoincludes angled shoulder 186 to deflected fluid back toward bypasspassage 164B. Fluid is, however, prevented from continuing to flowbetween outlet 160B and adapter 171 by the presence of seal 172. Assuch, fluid flows from porting 165B to bypass passage 164B to link upwith a different outlet and leave valve block 112.

FIG. 11A is cross-sectional view of a second embodiment of double-sealedcross-port fitting 125B in a pass-through configuration. FIG. 11B is across-sectional view of double-sealed cross-port fitting 125B of FIG.11A in a bypass configuration. In the embodiment of FIGS. 11A and 11B,fitting 125B includes all of the same features as the embodiment ofFIGS. 10A and 10B save channel 180. Additionally, in FIGS. 11A and 11B,seal 174 is switched to face seal 188. Face seal 188 circumscribesportion 176B and engages axial surface 190 of first portion 176A. Whenfitting 125B is threaded into bore 160B, face seal 188 is compressedbetween axial surface 190 and a corresponding axial surface of bore160B. In the embodiment shown, face seal 188 comprises a polymeric faceseal having generally flat axial facing surfaces. Specifically face seal188 is comprises of an inner metallic ring around which a polymericwasher is fitted, as is known in the art.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1. A series progressive divider valve comprising: a valve bodycomprising: a fluid inlet extending into an exterior of the valve body;a plurality of stations disposed in the valve body and extending from afirst end to a second end, the plurality of stations comprising: aplurality of piston stations extending axially through the valve bodyfrom the first end to the second end, each piston station comprising: apiston bore connecting the first end to the second end; and a pistondisposed within the piston bore; and at least one bypass station fluidlyisolating the first end from the second end, the bypass stationcomprising: a first fluid passage extending from the first end to afirst position inside the valve body; and a second fluid passageextending from the second end to a second position inside the valvebody; a plurality of outlet bores extending into the valve body, theplurality of outlet bores comprising: a first set of outlet bores; and asecond set of outlet bores; and porting forming a plurality passagewaysconnecting the stations to each other and with the plurality of outletbores such that when high pressure fluid is applied to the inlet each ofthe pistons reciprocates from the first end to the second end insequence.
 2. The series progressive divider valve of claim 1 whereineach piston station further comprises: a first end cap enclosing thefirst end; and a second end cap enclosing the second end.
 3. The seriesprogressive divider valve of claim 1 and further comprising: a firstpassage extending from the first end of a first piston station to thefirst position; a second passage extending from the second end of thefirst piston station to the second position; a third passage extendingfrom the first end of the bypass station to a second piston station; anda fourth passage extending from the second end of the bypass station tothe second piston station.
 4. The series progressive divider valve ofclaim 1 wherein the bypass station further comprises: a dividerseparating the first fluid passage from the second fluid passage betweenthe first and second positions.
 5. The series progressive divider valveof claim 4 wherein the bypass station can be converted to a pistonstation by removing the divider.
 6. The series progressive divider valveof claim 4 wherein the divider comprises an integral portion of thevalve body.
 7. The series progressive divider valve of claim 6 whereinthe bypass station comprises: a first stub bore extending from the firstend to the divider at the first poistion; and a second stub boreextending from the second end to the divider at the second position. 8.The series progressive divider valve of claim 6 wherein an envelope ofthe bypass station fits within an envelope of a piston station such thatthe bypass station could be machined to be converted to a pistonstation.
 9. The series progressive divider valve of claim 4 wherein thedivider comprises a portion of a dummy piston positioned in a pistonbore extending between the first end and the second end.
 10. The seriesprogressive divider valve of claim 9 wherein the dummy piston comprises:a first end surface; a second end surface; and a dummy shaft extendingfrom the first end surface to the second end surface, wherein the dummyshaft is approximately equal in length to the piston bore, the dummyshaft comprising: a seal portion comprising the divider and having adiameter engaging the piston bore to seal the first fluid passage fromthe second fluid passage; and first and second flow portion outward ofthe seal portion that permit fluid flow between the dummy shaft and thepiston bore.
 11. The series progressive divider valve of claim 10wherein the seal portion includes a groove having a seal.
 12. The seriesprogressive divider valve of claim 1 wherein each of the pistonscomprises: a first end surface to define part of a first end chamberwithin the piston bore through which it extends; a second end surface todefine part of a second end chamber within the piston bore through whichit extends; a first undercut to define part of a first internal chamberwithin the piston bore through which it extends; and a second undercutto define part of a second internal chamber within the piston borethrough which it extends; wherein a distance between the first endsurface and the second end surface is less than a distance between thefirst and second ends of the piston stations.
 13. A method ofmanufacturing a series progressive divider valve, the method comprising:machining a plurality of piston bores into a parallelepiped valve blockthat extend from a first surface to a second surface; machining firstand second opposing stub bores into the first and second surfaces,respectively; and machining a plurality of passages connecting theplurality of piston bores and the opposing stub bores to each other suchthat first ends of the piston bores and the first stub bore are fluidlycoupled and second ends of the piston bores and the second stub bore arefluidly coupled.
 14. The method of manufacturing a series progressivedivider valve of claim 13 and further comprising: inserting a pluralityof pistons into the plurality of piston bores; and closing the first andsecond ends of the piston bores and the first and second stub bores witha plurality of end caps.
 15. The method of manufacturing a seriesprogressive divider valve of claim 13 wherein the first and second stubbores are machined using a sub-set of machining instructions used tomachine the plurality of piston bores.
 16. The method of manufacturing aseries progressive divider valve of claim 13 wherein: each of the pistonbores comprises an first envelope; and the first and second stub borestogether comprise a second envelope; wherein the second envelope fitswithin the first envelope.
 17. The method of manufacturing a seriesprogressive divider valve of claim 13 wherein the first and second stubbores could be converted to a piston by performing the step of machininga plurality of piston bores at the location of the first and second stubbores.
 18. A series progressive divider valve comprising: a valve bodycomprising: a fluid inlet extending into an exterior of the valve body;a plurality of piston bores extending through the valve body from afirst end to a second end; a plurality of outlet bores extending intothe valve body; and porting forming a plurality passageways connectingthe piston bores to each other and with the plurality of outlet bores; adummy piston extending through one of the plurality of piston bores tofluidly isolate the first end from the second end; and a pistonextending through each of the remaining piston bores; wherein when highpressure fluid is applied to the inlet each of the pistons reciprocatesfrom the first end to the second end in sequence.
 19. The seriesprogressive divider valve of claim 19 wherein the dummy pistoncomprises: a first end surface; a second end surface; and a dummy shaftextending from the first end surface to the second end surface, thedummy shaft comprising: a seal portion comprising: a groove; and a sealpositioned in the groove; and first and second flow ends outward of theseal portion, the first and second flow ends having diameters smallerthan that of the seal portion.
 20. The series progressive divider valveof claim 19 wherein: a height of the dummy shaft is approximately equalto a distance between the first and second ends of the piston bore intowhich it is inserted; and a height of each of the plurality of pistonsis less than a distance between the first and second ends of the pistonbore through which each extends.